CVE-2021-31948Network attack vector

Authenticated content spoofing

Published Jun 8, 2021 · Updated Aug 3, 2024

Spoofing in Microsoft SharePoint 2013 SP1, 2016, and 2019 allows remote authenticated users to expose data and alter content. Microsoft has not published the affected request handler or the operation it performs incorrectly on untrusted input. Exploitation requires SharePoint privileges and user interaction; affected builds are before 15.0.5353.1000, 16.0.5173.1000, and 16.0.10375.20000, respectively.

CVSS severity7.6
High
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Spoofing in Microsoft SharePoint 2013 SP1, 2016, and 2019 allows remote authenticated users to expose data and alter content. Microsoft has not published the affected request handler or the operation it performs incorrectly on untrusted input. Exploitation requires SharePoint privileges and user interaction; affected builds are before 15.0.5353.1000, 16.0.5173.1000, and 16.0.10375.20000, respectively.

The record

CVE
CVE-2021-31948
Published
Jun 8, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Microsoft SharePoint Foundation 2013
Classifications
Unavailable
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.0.0 <15.0.5353.1000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Foundation 2013version=15.0.0 <15.0.5353.1000
Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5173.1000
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10375.20000

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
7.6Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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